Quaternary landscape history determines the soil functional characters of terroir

摘要

The soil functional properties that characterise the terroirs of a denomination of origin area are products and witnesses of the Quaternary events, natural and human induced, which occurred in that landscape. Knowing the Quaternary history can enhance the awareness of stakeholders about the possible environmental and economic losses that can derive from irrational soil management, which can lead to the worsening or loss of irreproducible soils of the best terroirs. In the "Vino Nobile di Montepulciano" wine territory, a four-year research project was conducted on the relationships between the soil and the viticultural and oenological behaviour of the Sangiovese vine. The study soils of the Montepulciano vineyard ranged notably in fertility conditions and functional characters, even when formed on the same kind of sediments. The grape production and vintage, as well as the organoleptic characteristics of the wine, depended on the kind of soil. The wines obtained from a first group of soils had a good structure and typicity, but the stability of the wine's sensorial profile from different vintages was low. A second group exhibited good structure, typicity, and a good stability of wine sensorial profile. A third group had the highest values of yield per vine, mean cluster weight, 100 berries weight and total acidity. Also, sugar content level and sugar accumulation rate were the lowest of all vineyards. Wines showed low structure, low typicity, and high astringency in all the years of the research. The oldest soils of the Montepulciano vineyard started their formation during the Pleistocene. During the middle Holocene, humans deeply influenced pedogenesis, but it is during the last 50 years that the intensity of anthropic action has reached its maximum. Pre-plantation activities of the new specialized vineyards upset the land. Where soils before vine plantation were deep and rather homogeneous, functional characters remained the same, whereas they changed significantly where soils were shallower. Shallow soils on marine clays, in particular, have been very vulnerable to change. The best soils for Nobile di Montepulciano wine production, that is, those belonging to the second group, were Pleistocene and Holocene paleosols, formed as a consequence of unique natural and human induced geomorpho-logical events. Therefore, they should be considered as cultural heritages.